Tweba (formerly Tweebay) aims to bring the power of Craigslist and eBay to the swap meet-like community of Twitter, allowing users to sell and buy goods as they stream in real time.
You can sign-up/log-in to the service using your Twitter or Facebook account.
Does the UX ring a bell? :)
Indeed, Tweba makes extensive use of the Twitter API... and of its user interface design.
Via VentureBeat
